DESCRIPTION: (Adapted from the applicant's abstract.) This is a prospective study of HIV infection in treated hemophiliacs and their spouses. The group will extend observations made on this cohort over the past five years, with a primary focus on asymptomatic HIV-infected patients, following the outcome in the remaining patients in light of prospective observations already made. The group will (1) measure course of HIV infection, (2) study potential cofactors in the pathophysiology of HIV infection, (3) assess the kinetics of host-virus interaction through the use of plasma cultures, specific antibody titers and markers of immune changes detected by flow cytometry and immune function assays, (4) investigate the immunology of asymptomatic stable infection, and (5) monitor sentinel populations of transfused anti-HIV-negative patients and spouses of anti-HIV-positive patients for risk of seroconversion. This will be a five year cohort study of transfused anti-HIV-positive hemophiliacs, a comparison group of transfused anti-HIV-negative hemophiliacs, and family member controls. Subjects will be seen once to twice yearly for clinical assessment, viral studies, immunophenotyping and immune function studies. Survival analyses will be done using data from the beginning of this study in January, 1990, and also by combining these data with the larger TSS database for which there are already four years of follow-up.